Single-cell RNA-sequencing analysis of fibrotic human lungs has recently identified novel pathological cell populations that drive disease progression; however, little is known about the impact of anti-fibrotic therapies on these cells.

We investigated the effects of bexotegrast (PLN-74809), a dual inhibitor of TGF-? activating integrins ?_V?₆ and ?_V?₁ currently in development for the treatment of idiopathic pulmonary fibrosis (IPF), on pathological cell populations in fibrotic human lung tissue by single nuclei RNA-sequencing (snRNA-Seq) analysis of precision-cut lung slices (PCLS).

PCLS prepared from lung explants from patients with IPF were cultured for 7 days in the presence of bexotegrast or vehicle. Single nuclei were isolated from PCLS and processed using 10x Chromium 3? kits.  Sequenced libraries were processed using CellRanger and analyzed using Seurat and BBrowserX.

snRNA-Seq analysis of fibrotic PCLS identified several unique cell populations important to IPF pathology, including aberrant basaloid cells and high collagen-producing CTHRC1⁺ fibroblasts. Treatment with bexotegrast significantly reduced total fibroblast expression of TGF-? pathway and scar-associated genes (e.g. COL1A1, TIMP1) (FDR<0.05), while also lowering the number of CTHRC1⁺ fibroblasts. Bexotegrast treatment also significantly reduced the expression of epithelial-mesenchymal plasticity-related genes (e.g. COL1A2, VIM, FN1) in aberrant basaloid cells (FDR<0.05).

snRNA-Seq analysis of fibrotic human PCLS treated with dual ?_V?₆/?_V?₁ integrin inhibitor bexotegrast revealed clear reductions in pro-fibrotic gene expression within cell populations important to IPF pathology.